| 摘要 |
1,088,551. Container closures. VISCOSE DEVELOPMENT CO. Ltd. Feb. 4, 1965 [Feb. 14, 1964], No. 1700/64. Heading B8T. A tubular blank of thermoplastic material which has been rendered heat shrinkable is placed on a former 2 and heated causing it to shrink on to the former; it is then cooled and removed, the dimensions of the former relative to those of the blank and the initial shrinkage characteristic of the blank being such that after removal the blank retains sufficient latent shrinkage to allow subsequent application of the closure, so formed, to a container by further heat shrinkage. As shown the blank forms a frusto-conical closure 1a with a flange 1 which engages a rebate around a closure disc 4 placed on the former, so that the closure and disc are removed together as a unit. The closure and disc may be attached by welding. In a modification a plug depends from the disc, Fig. 5, not shown, which has a circumferential groove into which a part of the closure is shrunk. The former may comprise a sleeve 2a, Fig. 3, not shown, and a plunger 2b facilitating closure removal; it may be a unitary structure, Fig. 4, not shown, with a central passage 5 for compressed air for unseating the closure. The latter construction may have a recess 6 in its top to receive the plug of the closure above described. |
